Constant clearance piston



N o n 2 n@ NE1L wmv. Umv. Ccm $.Td .mm Cwm.. N O C Nov. 24 1925.

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illlllllll INVE/vgoR. CSffamm ways ATTO NEYS.

9. All ot the sections are substantially shaped in form, the sections and 9 being' widest at their' upper ends and terminating;` in a reduced portion substantially pointed at their lower ends, The sections C and T are similarly substantially V-shapcd, but their positions are reverse, that is their lower ends present the widest portion, and their upper ends the narrowest or pointed portion. The sections 8 and 9 term an integral part ot the groove section ot the piston and they also torni supports tor the wrist pin bosses indicated at The sections indicated at t5 and are entirely independent ot the piston as they are separated trom the sec tions 8 and 9 such separations being;` obtained by cutting or slotting,` the skirt or sleeve section alongfr the lines indicated at 10, 11 and 12. Means are, however, provided ter connecting' the sections 6 and 7 with relation to the sections 8 and 9, and these connections are obtained by ribbing the inner side ot the piston as indicated at 13, lll and 15. ln other words it might be stated that the sections G and 7 are connected to the sections S and 9 by means et the ribs 13, 14 and 15. The rib 13 terms a connection between the lower adjacent ends ot the cctions (l, 7 and 9. The rib 15 terms av cennection between the opposite adjacent lower ends ot the sections G and 7 and the section S. The rib 14e terms a connection between the upper ends et the section (l and the sections 8 and 9, and the rib 14nu toi-ms a connection between the upper end ot the section 7 and the upper opposite ends of the sections 8 and 9. ln other words the sections G and 7 are supported by two ribs at their lower ends and by a single rib at their upper or pointed end, and the sections 8 and 9 are not only secured at their upper ends by termine an integral part with the ring section ol the piston. but they are also supported at their upper ends by the ribs 1-land l-l; the lower or pointed ends ot the sections S and 9 being` supported by the lower ribs 1.3 and 15, respectively.

From the toregoing;v it can be seen that a predetermined substantially fixed position is maintained between the respective sections, and that this position is mz'rintained by a plurality of connecting` ribs. It will further be seen, by referring' to Figs. 3 and that these ribs are arch shaped and as such term flexible connections between the sections, which permit either free expansion or free contraction ot the sections 'forming' the skirt or sleeve of the piston. Hence, if expansion takes place, the ribs will compress and thereby permit a uniform diameter to be maintained. Conif'ersely, as the piston cools, the ribs will expand and the same constant diameter will be maintained. It is duc to the flexibility of the connections between the respective sections that tree expansion and contraction can ta ke place, and it is tor the same reason that all (langer ot sizing and scoring` of the cylinders is prevented. A piston constructed as shown is also ideal 'trom a point ot lubrication, that is a considerable portion ot' oil is thrown by splashing` from the crank case up into the pistons and as the slots 11, 1() and l2 extend completely through the walls of the sleeve or skirt, it can readily be seen that the oil will leak out through these slots and as such will become evenly distributed over the cylinder walls. Similarly, excess oil will have a tendency to return to the grooves and uni'torm and even distribution of the lubricant is therefore maintained. A piston constructed in this manner is exceedingly light and such may be operated at high speeds. The wrist pins may le secured and lubricated in any suitable manner and as such may be changed to suit various conditions. The flexibility ot the sections with relation to cach other permits the use ot' any metal, regardless olf the coetlicient of expansion or the temperatures to which the piston is subjected, and it will similarly automatically take up wear, as a piston oi. this character may be litted with a clearance not to exceed 1/1000 ot an inch when tirst inserted. rl`hus, it is obvious that considerable wear may take place before piston slap will. be noticed even when startin;` cold, idling` or otherwise.

lVhile the present piston shows a skirt constructed of a number of sections, it is obvious that one or more sections may be employed, for instance where the piston is large and the side thrust during the power stroke is considerable, it might be advisable to only employ one section, and to place this section on the side opposite to that subjected to the power thrust. Such an arrangement would be ideal under many conditions as it still permits tree expansion and contraction ol the sleeve, and at the same time permits ample bearing surface on that side et the piston which is subjected to the greatest thrust.

Having thus described my invention, what I claim and desire to secure by Letters Patent isi l. In a piston of the character described a head, a ring` portion and a skirt portion, a substantially rl-shaped segment torming a part ot' the skirt, and a plurality ot arch shaped lugs connecting` the V-shaped segment to the skirt.

2. In a piston of the character described a head, a ring' portion and a skirt portion, a substantially tf-shaped segment forming` a part of the skirt, said V-shaped segment beingso positioned as to present its pointed or upper end towards the grrooved portion and its wide or base portion towards the lower end of the piston, a pair ot flexible ribs oonneoting the base portion oit the V- shaped section to the skirt, and a single flexible rib connecting the pointed end of the V-Shaped Segment to the skirt.

3. In a piston of the character described, :i head, a ringportion and a skirt portion, said skirt portion having a plurality of oblique slots formed therein dividing the skirt into four substantially V-Shaped seotions, two of said sections being formed integral With the ring portion, Wrist pin bosses Jformed integral with said sections, and flexible ribs connecting the other two sections to the integral sections Which carry the Wrist pin bosses.

CLEVELAND S. CUMMINGS. 

